The disturbing eco-documentary "The Last Mountain" charts the catastrophic effects of the mining technique called mountaintop removal on West Virginia's Coal River Valley.

That's a refreshingly blunt term: It means that the mining company obliterates the top of a mountain with dynamite to scrape out the coal beneath. The problem is that there are people living nearby.

Poisoned water, massive sludge dumps, floods, tumor clusters and other horrors are cited, and fingers are pointed squarely at Massey Energy, the state's largest coal company.

According to the film, 500 Appalachian mountains have been destroyed by the process. And it's not just the local people who suffer - burning coal, we're told, is a major contributor to the greenhouse effect.

The film, written and directed by Bill Haney ("The Price of Sugar"), follows the politics and economics of the region's dependency on Big Coal.

It also documents the efforts by local activists like Maria Gunnoe, a waitress and mother, to fight back on behalf of their beleaguered communities, with help from sympathetic outsiders like environmental lawyer Robert F. Kennedy Jr. There's a concluding pitch for wind power.

Robert F. Kennedy Jr. will appear Thursday at the Embarcadero Cinemas for a Q&A after the 7:20 p.m. show.

This story has been corrected since it appeared in print editions.

The Last Mountain

Documentary. Written and directed by Bill Haney. (Not rated. 95 minutes. At Bay Area theaters.)